Looking at the 4GHz Club listings, I'm seeing 1.4v for between 4 and 4.2GHz, which is way more than my 950 DO needed. 4GHz Club
And they are the better overclocks...yikes.
Your Scythe Mugen 2 isn't coping well enough.
The usual questions:
Is cooler mounted properly?
Not dirty or airflow obstructed?
Good TIM (Thermal Interface Material) like mx5 or better? (Too much can cause excess heat too so important just the right amount is used)
How many fans on Scythe?
How powerful are they?
Some recommend lapping, but be advised, results for lapping vary considerably.
Trick with True 120 was adding a washer under the mounting clamp to increase pressure, but again, results vary.
Google your Scythe compared to other coolers. Is it as good as Prolimatech Megashadow or True 120/Black? How close to their performance is it?
I say these things because not many are happy to run over 80, but Prime and other stress testers may be the only programs that can get your cpu that hot anyway. Personally I'd rather not go over 79.